Mean arterial pressure less than 70 mmHg or systolic pressure less than 100 mmHg persisting despite adequate fluid loading (in example with at least 1000 mL crystalloid or 500 ml colloid) unless central venous pressure (CVP) or pulmonary artery occluded pressure (PAOP) are elevated (e.g. CVP> 12 mmHg or PAOP > 14 mmHg).